Telescope Reviews: Re: Mallincam+16" F4.5 Lightbridge Dob+BrianReed RTP ?

I tried to find it... and failed

Heres the basic idea... (going from MEMORY here, haven't done Dob Visual or MCHP in months - weather has sucked, and I've been concentrating on AP on my GEM. So you might have to "think" through some of what follows!):

1) Mark a N/S Axis line on both the ground board of the RTP, and on the top plate - critical that this go through the exact center of both circles! Take your time here.

Now do the same thing for your dobsonian base plate; mark a radial line from the center of the azimuth rotational axis point out to the exact North edge.

precision is key on these measurements and lines!

2) put a metal bracket hanging over the edge, centered on those lines for both the OTA ground board, and the RTP brackets, such that if you use a screw or bolt down through the top one, it aligns through each down to the bottom one

then when you setup the RTP first (alone), make sure they are both aligned with each other and roughly aim the RTP to Polaris.

3) Put your OTA on the rig, and move the ENTIRE thing, keeping the top aligned to the bottom so that it points roughly at Polaris, close is ok for now

4) Then raise/lower your ota altitude only using Alt on the dob mount, and you can go Azimuth using the ground board of the OTA (which does mean that it no longer aligns to the RTP N/S lines... Do this to get polaris centered.

5) Mentally see how far off you are - in Azimuth only - and "scoot" the bottom RTP platform rotationally approximately that amount.

6) Then align all three, and see if you can center polaris, using ONLY Altitude on the Dob...

Repeat at step 5 until done.

I find it only takes about 5 minutes, 10 max, to get a Polar alignment good enough for Mallincamming.

I'll try to take some pictures sometime to make it more obvious.

But, the good news is the parts cost is about $5 or less, a few stainless steel "L" brackets and some bolts/screws...

HTH

Clear enough skies

--------------------
Dave

Imaging: MI-250+ADM/SBS/Optec Libra: C11Hyperstar,TMB80SS
Visual: XT10i RTP
TV: 31T5,22T4,17T4,12T4,13Ethos,8Ethos;2x Powermate,Paracorr, 1.6X Antares, Hyperion8-24Zoom
Cameras: Mallincam Color Hyper Plus, QHY8
Guider: SBIG STV eFinder
Key Add-ons: Gerbings Heated clothes, WilderSkiesObservatory(BYO#90), Speco 9"Monitor

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